We took the kit transmition and turned our robot into a six (6) wheel drive system,
http://sjharobotics.org/media/pictures/100.JPG , that has 4 different speed programmed into the code. We run at 75% our speed without holding any button. We also have 25%, 50%, and 100% speeds. The link to the picture is actually of our robot about two weeks before ship time. We actually traded out one of the motors because it was to loud, but the new one isn't as loud. We can actually program out robot to go even faster, but we drive well at 75%, and have great control as well. At 100% our robot is very fast, and at 125% we fear it is too sensitive, making the robot spin in place if you move the control even a little.